Muscle Sprains and Strains

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Muscle sprains and strains facts

A sprain is abnormal stretching or tearing of a ligament that supports a joint.

A strain is abnormal stretching or tearing of a muscle or tendon.

Sprains and strains may be caused by repetitive activities or by a single event.

The diagnosis of a sprain or strain usually can be made after the healthcare professional takes a history of the injury and performs a physical examination. Depending upon the situation, X-rays, CAT scan, or MRI scan may be needed to help make or confirm the diagnosis.

RICE (rest, ice, compression, and elevation) are the keys to treatment.

Most sprains and strains resolve with time, but occasionally other treatment, including physical therapy and surgery, may be required.

Anti-inflammatory medications may be helpful in decreasing the pain and inflammation of the injury.

What is the difference between a sprain and a strain?

A sprain is an injury to ligaments, while a strain is an injury to muscle or tendon tissue.

How muscles work

The purpose of muscles is to allow the body to move. A muscle attaches to bone, either directly or by way of a tendon, on each side of a joint. When the muscle contracts, the joint moves through its range of motion. The muscle that you feel underneath your skin is really made up of many smaller bundles of muscle fibers called fascicles. These, in turn, are made up of individual muscle fibers that are crosslinked to allow them to slide back and forth within the fascicle. Sliding together causes the muscle fibers to shorten and the muscle to contract and move the joint. The fibers return to their resting position when the fibers elongate and allow the joint to relax.

The transition of muscle to tendon happens gradually as muscle fibers give way to tendon fibers before the bony attachment occurs. The anatomy of each tendon is different and depending upon their location in the body, the tendon portion may be very short or very long. A strain is damage caused by an overstretched muscle or tendon, causing their fibers to be pulled apart and lose the ability to contract. The severity of injury depends upon the amount of tissue that is damaged. The muscle fiber may be just stretched, partially torn, or completely torn apart. The most common cause of the injury is overuse, which weakens the muscle. Muscles and joints are forced to perform movements for which they are not prepared or designed. An injury can occur from a single stressful incident, or it may gradually arise after many repetitions of a motion. The damage can occur in three areas: the muscle itself, the muscle tendon intersection where the muscle fibers transition to tendon fibers, or the tendon itself. Strains are described by the severity of damage in three grades:

Grade 1 strains usually cause stretching of a few of the muscle fibers.

Grade 2 injury is more significant damage and some muscle fibers are damaged and torn.

Grade 3 injury is a complete rupture of the muscle.

How joints work

Joints are stabilized by thick bands of tissue called ligaments that allow the joint to move only in specific directions. Some joints move in multiple planes. Therefore, they need more than one group of ligaments to hold the joint in proper alignment. The ligaments are anchored to bone on each side of the joint. If a ligament is stretched or torn, the injury is called a sprain.